Open word document using interop.word

Microsoft.Office.Interop.Word.ApplicationClass oWord1;

    Microsoft.Office.Interop.Word.Document oDoc1;

    object objFalse = false;

    object objTrue = true;

    object missing = System.Reflection.Missing.Value;

    Microsoft.Office.Interop.Word.Find fnd;

    Microsoft.Office.Interop.Word.Range rngdoc;

/// <summary>

    /// Open word document

    /// </summary>

    public string OpenDocument()

    {

        if (oWord1 != null && oDoc1 != null)

        {

            oDoc1.Close(ref objTrue, ref missing, ref missing);

            oWord1.Quit(ref objTrue, ref missing, ref missing);

            while (Marshal.ReleaseComObject(oDoc1) != 0)

            { }

            while (Marshal.ReleaseComObject(oWord1) != 0)

            { }

            oDoc1 = null;

            oWord1 = null;

        }

        if (oWord1 == null && oDoc1 == null)

        {

            //If word object is nul then create objects for accessing the wod document

            createObjects();

        }

        if (!Directory.Exists(Server.MapPath("~/Temp/")))

        {

            Directory.CreateDirectory(Server.MapPath("~/Temp/"));

        }

        object sFileName = Server.MapPath(strWordDocumentPath);

        oDoc1 = oWord1.Documents.Open(ref sFileName, ref objFalse, ref objFalse,

                     ref objFalse, ref missing, ref missing, ref missing, ref missing,

                     ref missing, ref missing, ref missing,

                     ref objTrue, ref missing, ref missing, ref missing);

        oDoc1.Activate();

        System.Object start = 0;

        System.Object end = oDoc1.Characters.Count;

        rngdoc = oDoc1.Range(ref start, ref end);

        string txtwordcontents = rngdoc.Text;

        txtPDFText.Text += txtwordcontents;

        return txtwordcontents;

    }

    /// <summary>

    /// this method is used to create objects for word application and word document

    /// </summary>

    private void createObjects()

    {

        try

        {

            oWord1 = new Microsoft.Office.Interop.Word.ApplicationClass();

            oDoc1 = new Microsoft.Office.Interop.Word.Document();

        }

        catch (Exception ex)

        {

        }

    }